glLoadMatrix
replaces the current matrix with the one whose elements are specified by
m. The current matrix is the projection matrix, modelview matrix, or texture
matrix, depending on the current matrix mode (see glMatrixMode).

The current
matrix, M, defines a transformation of coordinates. For instance, assume
M refers to the modelview matrix. If $v ~=~ (v[0], v[1], v[2], v[3])$ is
the set of object coordinates of a vertex, and m points to an array of
$16$ single- or double-precision floating-point values $m[0], m[1],. . .,m[15]$,
then the modelview transformation $M(v)$ does the following: